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Thread: Help please with boring head on a drill press

  1. #1
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    Help please with boring head on a drill press

    I started a new thread to be more specific with what I need help with. I was so happy I got my drill press aligned and squared up to the backhoe frame. I tried the boring head with the brazed carbide boring bars but it didn't go well. The 1st boring bar had the biggest shank but the carbide chipped trying to take a very light cut about half way down the bore. I didn't have the bore ground perfectly square top to bottom. Then I tried a boring bar with a smaller shank and it didn't have a big chip taken out but seemed to round itself and dull. I set the carbide pretty much straight up and down after watching a couple video's on the net. They didn't cut well at all and caused a lot of vibration. It might have been more due the carbide chipping or dulling.

    This tells me I need to strap and clamp the drill press better and get it as rigid as possible to the backhoe frame. I should be able to do this pretty easily. I plan to put a block of wood between the base of the drill press and the lower swing pivot (they should be very close to parallel) and then either use some 1/2" ready-rod and clamp them together or use a ratchet strap. Then I plan to put another block of wood cut to length between the drill press column and the upper pivot I'm boring and put a ratchet strap on it. I can also clamp the drill press table to the underside of the top pivot I'm boring with a wood spacer. I think this should hold the drill press as solid as possible top and bottom. I kind of doubt there'd be any warranty on the boring bars but the worst they can say is no. I read the import boring bars aren't very good and often need to be re-ground so they actually work. I plan to go to a machine shop supply to get a better quality boring bar. Should I try to find an HSS boring bar or would a better quality brazed carbide work? What about spending more for one with a replaceable insert and what type of insert? I've also read you need to turn faster with carbide but I think I'm at about 180 RPM which might be a little fast already. I'm doing a little under 3" bore. Is straight up and down the correct angle for the cutting head? What do you guys with machining experience suggest to give me the best chance of success? Thankfully I haven't ruined anything expect a couple cheap boring bars.
    Last edited by Welder Dave; 07-14-2022 at 12:07 AM.

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    Re: Help please with boring head on a drill press

    Simple formula for surface speed, and consequently rpm's. Steel cuts at 100sfm give or take. 100x4=400 Divide 400 by the diameter of the hole. 400/3=around 130rpm. You can run a bit faster with carbide, but I'd stay around 200rpm, considering you're probably doing interrupted cuts.

    Check the rake on the cutting tool. I like a bit of a positive rake. (The cutting edge pointed slightly up, not at 90* to the steel)

    Don't take too big a bite of the apple. Keep your depth of cut between 10-15 thou, and be patient. I'd imagine your setup isn't very rigid, being as it's not welded to the part. Lack of rigidity, and deep cuts, equals ruined tooling.........and ruined cuts. Same with your downfeed.......keep it slow.

    Use oil, just a squirt with each pass.

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    Re: Help please with boring head on a drill press

    I like HSS boring bars, but I grind them myself. If you don't want to do grinding, the brazed carbide is your best bet. Buy ones that are the thickest you can find that will fit your boring head, with the proper depth. Thicker bar means better rigidity

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    Re: Help please with boring head on a drill press

    Thanks Sam,
    I was only hitting one section of the bore with a very light cut. Is there a minimum amount you need to remove? Hopefully getting the drill press as solid as possible will make a big difference. I think someone posted that HSS is more forgiving. I have some Rapid tap cutting oil I can use and will tip the cutting edge forward a touch.
    Last edited by Welder Dave; 07-14-2022 at 12:50 AM.

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    Re: Help please with boring head on a drill press

    Quote Originally Posted by Welder Dave View Post
    Thanks Sam,
    I was only hitting one section of the bore with a very light cut. Is there a minimum amount you need to remove? Hopefully getting the drill press as solid as possible will make a big difference. I think someone posted that HSS is more forgiving. I have some Rapid tap cutting oil I can use and will tip the cutting edge forward a touch.
    High speed steel most certainly will be for forgiving for interrupted cuts, thermal shock, and that sorta thing. Keep in mind that carbide is VERY brittle. Hard, but brittle.

    You can make your own tooling fairly easily. I'm going to add a couple links to videos about grinding HSS, grinding carbide, and making your own tooling in a separate post. I think all the videos are long-ish format. I like to watch them when I'd otherwise be watching TV, eating lunch, or scrolling through Weld Web.

    It's also worth noting (and it's noted in one of the videos I'm going to link to) that import (China) brazed carbide tooling is absolute junk! At least the stuff I've seen is. Pay close attention to the cutting geometry of the boring bar you're using. The Chinese crap tends to have a HIGHLY negative cutting geometry, due to the carbide being forward of center.... I'll make a doodle. 1 second...

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    Re: Help please with boring head on a drill press

    Circle is boring bar, rectangle is carbide, interrupted line in centerline, Centerpoint is blue. Grey lines are where I suggest you grind the carbide to to get proper geometry.

    Edit: not exactly... but close enough. I'd give more support to the cutting edge (as much as you can without rubbing when cutting.

    Also, excuse the ugly doodles. I did that on my cellphone.

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    Re: Help please with boring head on a drill press









    Ok... I have videos from other channels to link to, but these are a start

    I know those don't relate directly to boring bars (I think... haven't seen those videos in a long time), but a boring bar is just like any other lathe tool. The drill bit video... I dunno. Shows cutting geometry? The HSS grinding video does a better job of it for this application, though. TOT makes some good content.

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    Re: Help please with boring head on a drill press

    And somewhere in THIS video is where Tony talks about the chity import boring bars he has and how he fixes them.

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    Re: Help please with boring head on a drill press

    I'm sure the boring bar set I got is imported, probably from China. HSS seem to be hard to find. Are the indexable a good option?

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    Re: Help please with boring head on a drill press

    Quote Originally Posted by Welder Dave View Post
    I'm sure the boring bar set I got is imported, probably from China. HSS seem to be hard to find. Are the indexable a good option?
    Indexable carbide tooling is industry standard. It has pretty much taken over. So, yes. They cost more, though. That's why I didn't mention it. That and I'm not in a position to give advice on what inserts to buy.

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    Re: Help please with boring head on a drill press

    Also, how big is the bore? Since you're having to order stuff, anyway....


    Keep in mind this is a post beer...

    What about buying a taper shank that fits your drill press, welding a large diameter piece of bar stock to it, cross drilling it to fit a piece of drill rod (HSS round rod) and then drilling and tapping holes that intersect the first hole, so that you can lock the drill rod in place.

    All you have to do then, is grind the drill rod into a decent cutting geometry, stick it in your newly made tool, adjust the stick out so you have about a... maybe a 10 thou cut? And go to town.

    Just like a line boring machine... makes sense, considering you're doing the job of a line borer

    https://www.amazon.com/ApplianPar-Sl...a-849380364223

    It doesn't have to be anything fancy and runout doesn't matter at all, since it's a single point cutting tool. Just make sure the Morse taper stays relatively concentric. Just make sure you don't put too much heat in the part when you weld it.

    The link is to literally the first result I saw on Google.

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    Re: Help please with boring head on a drill press

    Bore is just under 3 inch. I'm pretty limited as to tools. I have a couple angle grinders. Hoping I can find a decent boring bar that isn't too expensive. I think solidly strapping and/or clamping the drill press to the backhoe frame will make a big difference once I have a decent boring bar. When I checked the run out on just the arbor is was the same as the morse taper on the drill, .003". I have an adjustable boring head so I could probably grind a 1/2" piece of drill rod to fit in it. Thanks so much for your help 52 Ford!

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    Re: Help please with boring head on a drill press

    Quote Originally Posted by Welder Dave View Post
    Bore is just under 3 inch. I'm pretty limited as to tools. I have a couple angle grinders. Hoping I can find a decent boring bar that isn't too expensive. I think solidly strapping and/or clamping the drill press to the backhoe frame will make a big difference once I have a decent boring bar. When I checked the run out on just the arbor is was the same as the morse taper on the drill, .003". I have an adjustable boring head so I could probably grind a 1/2" piece of drill rod to fit in it. Thanks so much for your help 52 Ford!
    Not a problem at all. I'm happy to help.

    Here's a good video of a guy doing some line boring on a D10 dozer component. If you're in a hurry, skip to maybe 3:30.

    Keep in mind that this bar is supported on both ends (and pretty large in diameter), so he can take a heavier DOC.

    Maybe try and make a tool like this if the boring bar doesn't prove rigid enough. I wouldn't count on a perfect surface finish from that drill press head, though. Might wanna follow it up with a cylinder hone or something, rather than trying to chase down a perfect surface finish with the boring head.

    Mill spindle bearings and drill press bearings are a lot different... I'm no expert, but I can point you to a YouTube video from a guy who knows A LOT more about it than me.

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    Re: Help please with boring head on a drill press

    Having read through this, I feel like you're trying to make the drill press into a lathe instead of just using it for the power source?
    (Hopefully didn't miss anything)

    If true, study the video on line boring and note the welded supports on each end.

    If you make similar, and weld them on, I believe your rigidity issue will be solved.

    Then the drill press should essentially just be a power head with power feed.
    Dave J.

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    Re: Help please with boring head on a drill press

    Quote Originally Posted by MinnesotaDave View Post
    Having read through this, I feel like you're trying to make the drill press into a lathe instead of just using it for the power source?
    (Hopefully didn't miss anything)

    If true, study the video on line boring and note the welded supports on each end.

    If you make similar, and weld them on, I believe your rigidity issue will be solved.

    Then the drill press should essentially just be a power head with power feed.
    Exactly why a line boring setup is used when you can't bring the part to an appropriate rigid machine. Even with trying to open up a smooth hole problems would be encountered with a flimsy setup. With the proper bearing and bar setup a hand operated drill could provide the power.

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    Re: Help please with boring head on a drill press

    I just need to get the hole fairly round and square up and down. Then I can do some fine tuning for size with a flap wheel. Should be 2 to 3 thou. undersize for a shrink fit bushing. I plan to also use Loctite bearing retainer to fill any small gaps or out of roundness. Part of the problem is I've never done this so I'm sure experience would be a huge advantage. I think a better boring bar and really tightly strapping the drill press to the Cat will make a big difference. Other people have successfully done this so hopefully if I spend a bunch more time setting everything up as rigid as possible with a decent boring bar, I can get it close.

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    Re: Help please with boring head on a drill press

    I think I'm going to order a better boring bar made in the US. One place said a brazed carbide was about $29cad. Looking online I see there are also cobalt HSS boring bars. Would that be better for my application? Michigan Drill and Cutting Tools lists many styles of boring bars. I think the one below might be what I was quoted but not positive.

    https://michigandrill.com/catalog/pr...ucts_id=120559

    https://michigandrill.com/catalog/pr...ucts_id=106252

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    Re: Help please with boring head on a drill press

    Dave, although it's advertised as the bee's knees...........IIRC Cobalt is somewhat akin to HSS. I believe it's just an additive to make the HSS more wear resistant.

    If you feel you need the Cobalt, by all means get it...........if not....stick with the carbide. APT makes relatively medium quality stuff. I use their boring bars with fair success as long as I don't crowd them.

    I'll get the boring head out of the drawer,, and show you what I mean by positive rake. Pics in a little bit

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    Re: Help please with boring head on a drill press

    Name:  5F31B87F-4429-49EF-9BC4-B6B1316167D5.jpg
Views: 285
Size:  182.2 KB
    Not sure if this would work for you (my homemade setup). Bar is 1 1/2” dia and 20” long. Set up for 1/4” sq bit in center.
    3/4” unsupported stick out for tool might be too much.
    Want it? It yours just for shipping and I’ll cover 1/2 shipping.
    Use your drill press to power it.

    (I think I have a 3/8” sq reamer if 3/8” tool would support stick out)
    Last edited by labparamour; 07-14-2022 at 04:41 PM.

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    Re: Help please with boring head on a drill press

    Thanks Sam. I put cobalt HSS as it is an additive to the HSS. I think a better quality carbide specifically class C6 for steel might be the best as carbide can also handle higher speed. It should come properly ground as well. The boring bar set I bought just said precision boring bars and didn't mention what grade.

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    Re: Help please with boring head on a drill press

    Name:  roller54.jpg
Views: 284
Size:  163.0 KB When I talk about rake on a boring bar, I mean the attack angle. I could go even steeper than in the pic........I just popped the cutter in for your pic. Anything off line with the center line of the boring head is giving you positive rake. I could probably add another 10* to the rake, and still be in the zone........and making it even better at cutting material. Like I say.......this was a quick pop of the tool in the head.

    You can see that the cutting edge will slice instead of bull its way through the material. The angle allows the metal to flow up over the cutting face. This allows you to cut smoother, with less chatter, and less power. This is my own grind, but you can do pretty much the same thing, to some extent, with a brazed carbide insert. BTW.......this is the reason I grind my own tools........more ability to make the tool cut easier, and last longer. HSS is pretty good stuff if you have a grinder. A tool like this only needs a bit of dressing once in a while..........and it's cheap. A round HSS blank like this, costs about $8 where I buy them.

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    Re: Help please with boring head on a drill press

    Quote Originally Posted by labparamour View Post
    Name:  5F31B87F-4429-49EF-9BC4-B6B1316167D5.jpg
Views: 285
Size:  182.2 KB
    Not sure if this would work for you (my homemade setup). Bar is 1 1/2” dia and 20” long. Set up for 1/4” sq bit in center.
    3/4” unsupported stick out for tool might be too much.
    Want it? It yours just for shipping and I’ll cover 1/2 shipping.
    Use your drill press to power it.
    Thanks for the offer! I should be able to figure something else out if the boring head alone doesn't work. I don't have it with me right now but have to look to see if the middle hole on the bottom can be lined up dead center. If it can be, then maybe I could get a 1/2" flange bearing and make a mount for it on the bottom of the hole. I'd have to loosen the boring bar to move it further out to increase the size of the hole but you have to do that with a line boring jig anyway. I'm going to do everything possible to try for success in my next attempt.

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    Re: Help please with boring head on a drill press

    Quote Originally Posted by farmersammm View Post
    Name:  roller54.jpg
Views: 284
Size:  163.0 KB When I talk about rake on a boring bar, I mean the attack angle. I could go even steeper than in the pic........I just popped the cutter in for your pic. Anything off line with the center line of the boring head is giving you positive rake. I could probably add another 10* to the rake, and still be in the zone........and making it even better at cutting material. Like I say.......this was a quick pop of the tool in the head.

    You can see that the cutting edge will slice instead of bull its way through the material. The angle allows the metal to flow up over the cutting face. This allows you to cut smoother, with less chatter, and less power. This is my own grind, but you can do pretty much the same thing, to some extent, with a brazed carbide insert. BTW.......this is the reason I grind my own tools........more ability to make the tool cut easier, and last longer. HSS is pretty good stuff if you have a grinder. A tool like this only needs a bit of dressing once in a while..........and it's cheap. A round HSS blank like this, costs about $8 where I buy them.
    I kind of figured that's what positive rake meant. I might have even had a tiny bit of negative rake. 52 Ford mentioned drill rod is HSS so I should be able to get that pretty easily and experiment if it comes to that. I'm sure glad the machine is at least in my pole shed. It would be a rusted mess if I had to try to do this outside. Lots of rain here the last month or so but looks like next week is finally going to be nice all week.

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    Re: Help please with boring head on a drill press

    Name:  roller55.jpg
Views: 278
Size:  159.6 KB Cranked her over a bit further. The ruler is your material surface(sorta). You can see how aggressive the tool angle is, in relation to the material. This is the beauty of grinding your own tools. I love this stuff.

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    Re: Help please with boring head on a drill press

    Quote Originally Posted by Welder Dave View Post
    I kind of figured that's what positive rake meant. I might have even had a tiny bit of negative rake. 52 Ford mentioned drill rod is HSS so I should be able to get that pretty easily and experiment if it comes to that. I'm sure glad the machine is at least in my pole shed. It would be a rusted mess if I had to try to do this outside. Lots of rain here the last month or so but looks like next week is finally going to be nice all week.
    Don't buy drill rod. It isn't straight. Get HSS tool blanks. Whole different animal. Finish ground to perfection, either in square, or round. You need to start off with a straight piece, or your tool will always be a little weird.

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